Polistes spp. Latreille, 1802

Paper wasp

Slender wasps with open umbrella nests under your eaves, docile neighbours and caterpillar hunters.

Order: Hymenoptera
Family: Vespidae
Group: Wasps, hornets & bees
Ontario status: Established, native (several species)

Why it matters

Low sting risk, high garden value, each colony removes large numbers of caterpillars. Nests directly over doorways are the main conflict; elsewhere they are allies.

Origin

Native; several species across Ontario, including the common Polistes fuscatus.

Behavior

Hunts caterpillars to feed its young, genuinely useful in gardens. Relatively docile; stings usually only when the nest is grabbed or bumped. Legs dangle distinctively in flight.

Living conditions

Builds small open paper combs, the classic umbrella shape, under eaves, deck railings, window frames and shrubs.

Signs of presence

Umbrella-shaped open paper nests under eaves and railings
Slender wasps with dangling legs visiting gardens
Chewed wood fibres on weathered deck rails (nest-building material collection)

Weaknesses

Small colonies (dozens, not thousands), low sting risk
Open nests are visible and easy to assess
Single-season; winter ends the colony
Nests in predictable spots, early-season removal of starter nests prevents the colony

Myths and facts

Myth All wasp nests must be destroyed.
Reality Paper wasp colonies are small, seasonal and beneficial. A nest under a high eave away from doors is free caterpillar control, removal is only warranted at conflict points.

Research notes

Morphology

Workers 13-17 mm; slender, long-waisted, reddish-brown to black with yellow markings (variable). Long legs dangle in flight, the field diagnostic. Nests: open comb without an envelope, umbrella-shaped, suspended by a stalk.

Diagnostics

Confirm by: slender build, dangling legs in flight, open umbrella comb nest, relatively calm behavior.

Easily confused with

Mud dauber, Sceliphron caementarium Mud daubers have an extremely thread-like waist and build mud tubes, not paper combs; they never defend a colony.
Yellowjackets, Vespula spp. Yellowjackets are stocky, fast, and nest in enclosed cavities; paper wasps are slender with visible open nests.

Life cycle

Egg: Foundress builds the stalk and first cells in spring, laying eggs as she builds
Nymph or larva: Larvae in open cells, fed chewed caterpillars by the foundress, then by workers
Adult: Colonies of a few dozen; males and new foundresses in autumn; mated foundresses overwinter in sheltered cracks
Egg to adult: Approximately 4-6 weeks per generation
Generations per year: One colony cycle; overlapping worker broods through summer

Development

Complete metamorphosis: egg → larva → pupa → adult. Primitively eusocial: foundress starts alone, daughters become workers.

Reproduction

Foundress (sometimes small cooperative groups) initiates; workers are daughters; autumn produces the next year's foundresses.

Distribution

Native range: North America (native species); P. dominula introduced from Europe
Ontario: Common; P. fuscatus widespread, P. dominula expanding
Global: Worldwide genus

Ecology

Open-nesting makes colonies vulnerable to weather and predators, the trade-off for low construction cost. Important caterpillar predators in gardens and old fields. P. dominula (European) competes with native P. fuscatus where ranges overlap.

Resistance

Not applicable, no insecticide resistance documented.

IPM implications

Tolerance-first biology: small, seasonal, beneficial colonies at non-conflict sites need no action, a defensible professional recommendation. Conflict nests (doorways, play areas) are removed mechanically or treated at night by operators. Prevention is early-season: knocking down starter combs in spring (when the foundress is alone) prevents the colony at near-zero risk. Client education, 'this nest is an asset', is part of the service.

Chemical ecology

Nestmate recognition via cuticular hydrocarbons; foundress dominance maintained behaviorally and chemically; caterpillar prey located visually.

Genetics and DNA

No reference genome published as of 2026.

Taxonomy

Hymenoptera: Vespidae. Genus Polistes Latreille, 1802. Ontario species include P. fuscatus (northern paper wasp); the European P. dominula is established in parts of eastern North America and expanding.

Open questions

Competitive displacement of native P. fuscatus by invasive P. dominula in Ontario; foundress overwintering site ecology.

References

Evans & Eberhard (1970), The Wasps (Univ. Michigan Press)
Reeve (1991 onward), Polistes social biology, primary literature
Penn State Extension, paper wasps